The present invention is related to reduction gears and, in particular, to a carrier frame used in a planetary gear system.
Gear reductions are often used in mechanical systems to provide a differential in the rates of rotation of an input shaft and an output shaft. Planetary gear assemblies are one example of such a reduction gear system.
Planetary gear assemblies may include, for example, an input shaft having a sun gear arranged coaxially with an axis of rotation of the input shaft. Planetary gears engage the sun gear in a radial arrangement about the sun gear, and engage a fixed ring gear that is concentrically arranged about the sun gear. The planetary gears are arranged between the sun gear and the ring gear. The planetary gears are supported by bearings (generally two per gear, or two bearing sets) that are mounted in a carrier frame. These bearings are arranged in two planes with a bearing supporting each end of the planetary gear at each of these two planes. These planes are commonly arranged such that one is on either side of the gear so that the gear is straddle mounted (where gear face load occurs between bearings). The bearing centers are closely aligned between the two planes to establish an axis of rotation about their center that is parallel to the axis of rotation of the sun gear.
In operation, a torsional force applied to the input shaft rotates the sun gear, which in turn, rotates the planetary gears that are coupled to the carrier frame resulting in the rotation of the carrier frame, and an output shaft connected to the carrier frame. The tooth count of each of the gears used collectively establishes the specific reduction ratio of the planetary gear assembly.